MYOFIBROBLAST REGULATION OF THE STEM CELL NICHE IN SHORT BOWEL SYNDROME

 描述（由申请方提供）：克罗恩病、缺血、创伤或放射性肠炎等疾病手术切除后功能性小肠表面积丧失可能导致短肠综合征（SBS），这是美国发病率、死亡率和医疗保健费用的重要原因。SBS患者通常依赖肠外营养来满足其营养需求。肠切除后，剩余的小肠上皮会产生适应性反应，增加绒毛高度、隐窝深度并增强营养和电解质吸收。然而，人类的适应性反应是不可预测的，可能需要长达两年的时间才能确定哪些患者将放弃肠外营养，即使对残留小肠长度进行了准确评估。这种临床变异性的机制基础尚不清楚。我们的申请旨在探索新的再生治疗方法，以提高小肠功能表面积，使用来自PI的大型SBS患者人群的患者活检。我们的方法将从我们的短肠综合征和肌成纤维细胞信号传导的临床前模型中观察到的干细胞生态位转化为具有治疗潜力的人类SBS研究。我们已经表明，肌成纤维细胞蛋白，epimorphin（Epim）调节隐窝分裂，肠上皮细胞增殖和肌成纤维细胞分泌功能的小鼠。与Epim-/-肌成纤维细胞共培养进一步增强WT小鼠隐窝肠样生长和表面积。我们的首要目标是增强增殖上皮反应和增加小肠表面积作为SBS的治疗策略。我们的总体假设是，调节肌成纤维细胞Epim及其靶点将增强人小肠生长，为SBS提供一种新的再生治疗方法。目标1将通过建立来自PI的SBS患者大队列的干细胞/肠样细胞和肌成纤维细胞培养物来直接转化我们的小鼠研究。我们将阐述与Epim缺陷型肌成纤维细胞共培养增加人类肠的生长的假设。我们将确定体外肠样组织的生长和增殖能力是否可以预测肠外营养的适应和断奶能力。目标2将解决两个假设。1. MF-隐窝上皮相互作用通过Epim缺失调节，以通过改变的Bmp、Hh和Wnt信号传导途径增加隐窝干细胞增殖和肠样生长。2. Epim在调节MF分泌中表现出上下文特异性抑制作用与促胞吐作用。我们的研究是重要的，因为我们将直接翻译我们的研究结果从临床前研究到人类研究的Epim删除的影响MF功能的干细胞龛。我们将扩大我们独特的临床收集的小肠隐窝干/肠样培养物从SBS患者，并产生一个国家的资源，为潜在的未来高通量筛选治疗剂，提高干细胞和隐窝细胞增殖SBS。Epim和由Epim缺失调节的可溶性因子的分泌代表了潜在的新的治疗靶点，以促进肠干/隐窝上皮细胞增殖，导致适应。.

 DESCRIPTION (provided by applicant): Loss of functional small bowel surface area following surgical resection for disorders including Crohn's disease, ischemia, trauma, or radiation enteritis may result in short bowel syndrome (SBS), an important cause of morbidity, mortality and health care costs in the U.S. SBS patients are frequently dependent on parenteral nutrition to meet their nutritional requirements. Following intestinal resection, the remaining small bowel epithelium mounts an adaptive response that increases villus height, crypt depth and enhances nutrient and electrolyte absorption. However, the adaptive response in humans is unpredictable and it may require up to two years to determine which patients will wean off parenteral nutrition, even with an accurate assessment of remnant small bowel length. The mechanistic basis for this clinical variability is unknown. Our application seeks to explore new regenerative, therapeutic approaches to enhance small bowel functional surface area, using patient biopsies from the PI's large SBS patient population. Our approach will translate observations from our preclinical models of short bowel syndrome and myofibroblast signaling in the stem cell niche into studies in human SBS that have therapeutic potential. We have shown that a myofibroblast protein, epimorphin (Epim) regulates crypt fission, gut epithelial proliferation and myofibroblast secretory function in mice. Co-culture with Epim-/- myofibroblasts further enhances WT mouse crypt enteroid growth and surface area. Our overarching goals are to enhance the proliferative epithelial response and increase small bowel surface area as a therapeutic strategy for SBS. Our overarching hypothesis is that modulating myofibroblast Epim and its targets will enhance human small bowel growth providing a novel regenerative therapeutic approach to SBS. Aim 1 will directly translate our mouse studies by establishing stem cell/enteroid and myofibroblast cultures from the PI's large cohort of SBS patients. We will address the hypothesis that co- culture with Epim-deficient myofibroblasts increases the growth of human enteroids. We will determine whether growth and proliferative capacity of enteroids in vitro can predict the ability t adapt and wean from parenteral nutrition. Aim 2 will address two hypotheses. 1. MF-crypt epithelial interactions are modulated by Epim deletion to increase crypt stem cell proliferation and enteroid growth via altered Bmp, Hh, and Wnt signaling pathways. 2. Epim demonstrates context-specific inhibitory vs. pro-exocytotic roles in regulating MF secretion. Our studies are significant because we will directly translate our findings from preclinical studies to human studies of Epim deletion's effects on MF function in the stem cell niche. We will expand our unique clinical collection of small bowel crypt stem/enteroid cultures from SBS patients, and generate a national resource for potential future high throughput screening of therapeutic agents that enhance stem and crypt cell proliferation in SBS. Epim and the secretion of soluble factors that are modulated by Epim deletion represent potential novel therapeutic targets to promote intestinal stem/crypt epithelial proliferation, leading to adaptation. .